The Wind, The Sun and The Nuclear – Part 1

What if the latest plan comes off? What if South Australia ends up with an on-going windfall of billions from foreign nuclear fuel disposal funds, and all we have to do in the short term is set aside a small patch of stable land, seal it and start lining up impregnable concrete-steel casks on it? Is that all we’d need? What if we see Australia’s regressive restrictions shortly lifted, and the next generation of nuclear energy debuted here in our front yard?

Some insist on using the word “dump”. It doesn’t look like any dump I’ve seen. Click on the image for more information.

The royal commission should allow us to answer these questions with high certainty. One further question which will be addressed is the impact potential energy generation may have on renewables – since it is in the terms of reference. I personally think it would be more constructively examined elsewhere. At worst it could perpetuate the imagined incongruity between nuclear and renewables.

I am quite prepared to be corrected.

Critical comparisons between the technologies – or is that between two different approaches to servicing demand? – are inevitable. But making the judgement that it must be one, not the other, is just tribalism. I think we’re all capable of better than that. The following analysis will strive for this impartiality – relying only on official numbers and minimum assumptions, and avoiding inaccessible technical language. What it won’t do is ignore what we’re trying to achieve with all this.

The Wind

The Ceres Project, to be constructed on South Australia’s Eyre Peninsula, is intended to be the nation’s largest wind farm yet at 600 megawatts (MW). This is 43% larger than MacArthur in Victoria. 197 turbines will be erected within a 600 square km area. The project has government approval, support through the state renewable energy target and also broad community support. It will require the first bit of major renewable energy-related transmission infrastructure proposed for the National Electricity Market (NEM) in an underwater high voltage direct current (HVDC) link to Adelaide.

We are all familiar with what it will produce – electricity to our homes, schools, hospitals, businesses and industry, bought and sold as kilowatt hours (kWh). How much? REpower estimate a capacity factor of 38% for their generators at this site. This means there will be perfect, windy days and nights that keep the turbine blades turning at full power, as well as times without wind (or merely a breeze too weak to reach the start-up speed and all wind speeds in between, but over yearly time spans it will all add up to enough to produce an average of 38% of rated power. Multiplying this figure – 418 MW – by the 8760 hours in a year gives 1,997,000,000 kWh. Over the course of a year all of these kWh will be effectively portioned out to meet the demand from our fridges, phone chargers, traffic lights, factories, and so on. It won’t be enough – SA produced over 12.2 billion kWh in 2013-14, and also imported plenty from Victoria – but it will be a substantial fraction.

However, that demand may be high at particular times when wind speeds have dropped. This has been studied by the independent market operator AEMO, for SA wind resources specifically. Based on a decade of data, for 85% of the time during peak summer demand periods, generation can be expected to reach 8.6% of capacity. This means that when we’re running our air conditioners, when hospitals and supermarkets need to keep stocks cold, and everything else is running besides, Ceres will have a high probability of supplying something like 51.6 MW out of an anticipated peak demand of 3250 MW (based on recent AEMO estimates). Remember, these are statistics from the independent market operator, not an anti-wind organisation or a thinktank.

This contribution factor is somewhat variable: 2014 calculations put it at 8.7%. However, it cannot be dramatically improved as it is a basic function of the intermittency of the resource.

Should we do this?

Yes – Ceres is ambitious, with many anticipated benefits for the region. The underwater cable can integrate modern fibre optic communication capacity to the peninsula. The SA grid and the wider NEM can handle more wind capacity if interstate connection upgrades also proceed. Overall emissions from the SA power sector will most certainly decrease further. Moreover, a recent analysis of generation technologies quantified the ecological advantages of deploying wind energy where appropriate.

The Sun

South Australia has no utility scale solar farms such as the recently connected Nyngan plant in NSW, but 2015 will see the commissioning of an elegant application of photovoltaic (PV) technology. 4 MW of panels spread over three water treatment ponds in Jamestown will apparently cut evaporation by 90%, and operate more efficiently through constant temperature moderation.

I don’t know how many treatment ponds are operated in the settled coastal areas of the state, but for the purpose of this analysis we want to extend this idea to 150 of them. The result would be 600 MW of efficient solar power that operates with a higher than average capacity factor of 17.65% (for PV, this is a function of the limitations of night and cloud cover). Similar to wind, taking the capacity factor-corrected output of about 106 MW over a year produces 468,700,000 kWh – meeting a somewhat smaller fraction of overall demand.

Of course, solar is considerably more regular than wind. Does this mean it’s better for meeting demand? AEMO has also looked at this, and for South Australia it estimated that the average PV output during maximum summer demand periods at 4 PM equates to 38% of installed capacity. That would be 228 MW from these ponds – about 7% of AEMO’s anticipated high end peak demand for the state.

This regularity can be taken into account by such things as demand side management – getting more load to line up with that maximum supply earlier in the day. This will only work to a point because Bureau of Meteorology figures inform us that we can depend on 224 days of no or minimal cloud. The other 141 will see output drop as low as approximately 25%.

Should we do this?

My word, yes. The elegance of boosting panel efficiency while reducing evaporation makes this a perfect application of the technology. I can’t think of a reason this shouldn’t be deployed on every suitable treatment pond.

The Nuclear

AEMO have not evaluated the benefits and challenges of integrating nuclear power into the SA system. After all, it’s somewhat beyond its remit. The closest we have is Heard and Brown’s exhaustive Zero Carbon Options report, which assessed the suitability of a proven Canadian-designed reactor as a “drop-in replacement” for the capacity and service provided by the ageing Port Augusta coal station.

The sort of nuclear power now being suggested is the next generation up. It is typified by GE Hitachi’s PRISM model, which was recently systematically evaluated for its ecological benefits. A twin unit plant, like that proposed for Sellafield in the UK, is expected to generate 622 MW for the grid, with an outage every 18 months for refueling. A 90% capacity factor is generally accepted for modern nuclear plants, so year on year we could expect 4,904,000,000 kWh from PRISM. Importantly, for a single year between refueling outages, this would be a total of 5,449,000,000 kWh, and during normal operation it would supply almost 20% of AEMO’s forecast upper peak demand.

In addition to steady electrical power, the generator would provide a stable frequency (the 50 hertz which all our devices operate at) as well as inertia – the ability of the electrical grid to cope with rises and drops in demand (and supply) in a stable way. Broadly, stability means less chance of blackouts. Wind and solar power can only supply these functions by addition of expensive, complex electronics. For power plants like PRISM – or the coal and gas that we’re used to – it is an inherent property of the rapidly spinning turbines.

While wind and sunlight, as fuels, are thought of as free, PRISM would not be burdened with fuel costs either – it consumes either fuel removed from conventional nuclear reactors or the ‘depleted uranium’ left over in the initial enrichment of that fuel. None of these materials are really useful for much else; they sit around, securely stored, and have never caused any occupational injuries. Even the radioactivity one might conceivably be exposed to is negligible.

How much is 0.10 μSv per hour?

Should we do this?

A PRISM plant would straight up replace South Australia’s remaining coal-fired capacity plus some of our old gas capacity. It would be the apex of a brand new, innovative 21st century industry that could directly and indirectly employ tens of thousands. It would also be necessary for dealing with the foreign material accepted into our proposed Spent Fuel Bank. Fortunately, the revenue from the Bank can apparently be expected to pay for the reactors.

There are plenty of challenges. It would be illegal under current federal law. Regulations would need to be adopted, though this has been recently and rapidly achieved in certain countries. While the group of materials, construction and service companies organise themselves, training of sufficient expertise would need to be sought, as well as a suitable site. Education would be required to address any and all public concerns. It would probably be at least two election cycles’ worth before the plant would come online, so bipartisan support would be rather crucial.

It should now be clear that comparing renewables and nuclear is unhelpfully simplistic. The above three (not two!) very different approaches to servicing the demand for the same product – electricity – each have fundamentally different features and advantages, along with perfectly surmountable challenges. All will serve to drive state power sector emissions down, facilitated by being part of a larger market.

In Part 2, we will examine what all this electricity is for; the cost, challenges and adjustments that we, as its consumers, will face in the future; and the new things we’re going to need it for if decarbonisation is our overriding goal.